Did you ever live with the fear that somebody may break into your system one day and steal your files? Well, those days are over, because you can now have an entire encrypted operating system.
Read what to do here
But the following guide is supposed to work with your actual Ubuntu 7.04 installation (no reinstall needed). Beware though: if you don't have the partitions setup like its shown below, this will NOT work.
I will NOT be held responsible for any data loss on your hard drive if this process will NOT work for you, so you have been warned: TRY THIS AT YOUR OWN RISK!